My partner plays a game and listens to a podcast for relaxing. In-game she turned off any sound but the constant ads every few minutes still start with sound. Is it possible to mute the game app in the Android settings?
Not sure about other phones, but for samsung you can get "Sound Assistant" from the Galaxy Store. This will let you split the sound, app by app in the default volume menu that appears when you use the volume buttons.
This feature unironically turned me from a decade long Samsung hater into a Samsung shill. The fact that it's still not in base Android is just embarrassing.
This and all the other tools featured in Good Lock, Pentastic, One Hand Operation +, Theme Park, Routines +. Crazy how many features integrate seamlessly into the samsung OS
On Samsung phones Samsung GamelauncherGaming Hub gives you the option to mute all game audio, but I'm afraid this is a Samsung exclusive feature.
Another feature I have on my Galaxy S10 is the ability to set different outputs for apps, ie. "bad sounds" from some app to phone speakers (which are muted), and the rest to my Bluetooth headphones.
On my phone this feature is called "Separate app sound" and is located in Settings > Sounds and vibration > Separate app sound.
It might also be a Samsung exclusive though.
Edit:
I have yet another, sadly probably Samsung exclusive, solution. Samsung Sound Assistant let's you set a different volume for each app (like Windows volume mixer).
Maybe what I will say is not exactly what you are looking for but it can help, try using RethinkDNS, it is an open source app that works as a firewall and can completely remove ads from many apps without doing anything special, you simply need to turn on the app and that's it.
I would also recommend "Auto mute", it is another open source app that cannot filter sound by app, but can filter by type of sound, for example, you can disable the audio of specifically game-type apps.
For example, I have Auto Mute configured so that it automatically silences all multimedia sound, so, if I watch a YouTube video it starts silently and when I increase the volume I can clearly hear it, but if I close the app and open another video, now the app would be silenced again until I manually turned up the multimedia sound again.